#include <stdio.h>
unsigned int Gcd(unsigned int a,unsigned int b)
{
    if(a>b)
    {
        return Gcd(a-b,b);
    }
    else if(b>a)
    {
        return Gcd(a,b-a);
    }
    else
        return a;
}
void main()
{
    unsigned int a,b;
    printf("Input two numbers:");
    scanf("%u,%u",&a,&b);
    printf("the greatest common divisor is %u",Gcd(a,b));
}
